1. Field of the Invention
The invention relates to a novel apparatus and method for extruding one material to surround a supply of another material.
2. Description of the Prior Art
U.S. Pat. No. 3,615,675 discloses an extruder that produces a dough tube filled with a suitable food material which is divided into pieces. U.S. Pat. No. 3,541,946 discloses a device for forming a cereal shell and simultaneously filling the shell with a suitable filler. The continuous tube of cereal material is then divided into pieces. U.S. Pat. No. 3,513,504 discloses a annular die for forming theremoplastic sheets; there is an air passage centrally of the die for expanding the formed tubular plastic structure.